A controller of a battery management system may coordinate the charging and discharging of a high-voltage battery system to ensure that each block or battery cell discharges and charges to the same voltage level. The battery management system may rely on a daisy-chained communication network (e.g., an inter-block communication network) that communicatively couples the controller to each block. The controller may act as a master node located at an initial position in the network and the respective monitoring and balancing circuits (also referred to herein as “balancing and monitoring circuits”) assigned to each block may act as individual slave nodes located at subsequent positions in the network.
During a broadcast phase of the network, the slave nodes may listen to a low-side bus interface and replicate broadcast data received via the low-side bus interface, via a high-side bus interface and up the chain, until the broadcast data reaches an addressed node. During a reply phase of the network, the direction of bus communication may be inverted. The addressed node may reply to the broadcast by transmitting reply data via the high-side bus interface and back down the chain. Each subsequent slave node in the network, below the addressed node, may replicate the reply data received via the high side bus interface to the low side bus interface until the reply data reaches the master node.
Each slave node may draw power needed for each phase of communication on the network from its respective battery block. By having to more frequently replicate broadcast and replies on the network, the slave nodes that are positioned towards the start of the chain (e.g., nearest to the master node) may consume more power, over time, than the slave nodes located near the end of the chain (e.g., furthest from the master node). For example, depending on the position of a particular node along the chain, the node may have to communicate a different quantity of bits and may have a different communication load (e.g., due to a variation in wire length and parasitic loads).
Therefore, implementing an inter-block communication network such as this may lead to an overall imbalance in communication related power consumption amongst the blocks. Since imbalance in the cell system leads to longer charging times and less overall battery capacity, a consistent imbalance in power consumption amongst the blocks due to intrinsically necessary communication power draw is undesired.